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Sunday, May 21, 2006

Birdsong Is My Favorite Part of Springby Ro Wauer

Each spring as the songbirds arrive or pass through our area, it is again time to remember some of their happy notes. It isn't easy to recall a couple dozen songs, especially those that haven't been heard since last spring. Some are easy, however. For me, I can always recall the songs of the eastern wood pewees, a plaintive "pee-ah-wee, pee-err;" the blue-gray gnatcatcher's lispy "spee, spee, spee;" black-and-white warbler's thin "wee-see" couplets; northern parula's buzzy "zzzzzzeeeeurp"; and the common yellowthoat's "witchy, witchy, witchy."

But that is only a start of the numerous songbirds that can usually be heard in spring. Some of the migrating songbirds sing only partial songs en route, apparently waiting until they reach their breeding grounds before delivering their full renditions. That can make it even more difficult. But nevertheless, it is still fun to try to identify, to remember, the songs from previous years. Some of the warbler songs are most difficult to separate, as they can sound very much alike. For instance, the song of the orange-crowned warbler, one of the songbirds that have overwintered in our area, can be confused with that of the Virginia's warbler, a closely related species. And the Nashville warbler, one of our most numerous spring migrant, sings a song that reminds me of that of the yellow-rumped warbler, another of our wintering species.

I have found that I often need to see them singing before I can properly remember which one is which. Right now I have several Nashville warblers in my yard. Nashvilles possess a gray head with noticeable white eye-rings, yellow throat and breast, and yellow-green upperparts. And when excited they often show a chestnut crown-patch. Their full song is delivered in two parts, the first higher and slower: "see-it see-it see-it, ti-ti-ti-ti-ti-ti."

Two additional, favorite northbound migrants to expect are the black-throated green and hooded warblers. Adult black-throated greens possess a yellow face, black throat and upper breast, yellow-green upperparts, and white wing bars. A gorgeous creature! Its full song is a husky "zee zee zee zoo zee." Hooded warblers are sexually dimorphic, in that the male looks different than its mate. Males possess a yellow face, coal black hood and neck, olive-green upperparts, and bright yellow underparts. Female are duller versions without the noticeable coal black hood and neck. Their song, though variable, can be described as a loud "weeta, weeta, wee-tee-o."

Many bird species possess a repertoire of songs, often singing different songs in order, one after the other. Our mockingbird has as many as 150 songs, while the brown thrasher can sing as many as 67 song types. And many wrens, especially the tropical wrens, often sing duets, so that one individual begins the song and its mate ends the song. And our common Carolina wren songs usually solicit songs from all the neighborhood Carolina wrens.

How many songs do birds sing is a single day? That varies with the species. Ornithologist Margaret Nice recorded 2,305 songs in a single May day for a song sparrow. She also reported that a black-throated green warbler sang 1,680 songs in seven hours. But the North American winner is the red-eyed vireo. Ornithologist Harold Mayfield recorded a Michigan red-eyed which sang 22,197 songs in a day.

Biologists tell us that birdsongs are utilized to identify the bird's territory, usually directed at other males, and to attract a mate. The song may also serve to convey a message. And it is hard not to believe that a spring migrant, en route to its breeding grounds, is not singing just because it is happy. But whatever their purpose, most listeners appreciate birdsong simply for their acoustical quality. For many of us, it would be an empty world without the sings of birds.